Frequent shoppers are healthier

An interesting article published in the April 2011 issue of J Epidemiol Community Health, Frequent shopping by men and women increases survival in the older Taiwanese population, is not too surprising. I didn't see the full article (not published yet?). But I think the reason frequent shoppers are healthier may be that they walk and use brains a lot, contributing to improvement of physical and mental health. What's a little surprising is the finding that "Highly frequent shopping may favour men more than women". Is it because shopping frequency varies much more among men than among women?

Sun UV to trigger Vitamin D and skin cancer: intensity matters?

I've never read a report about this but I have had this suspicion for a long time. On the one hand, we need to expose our skin to the sunlight, preferably on a daily basis, in order to let the body synthesize enough vitamin D. On the other, we don't want so much exposure as to cause skin cancer. All reports or articles I know simply advise moderation in exposure time. But I have a hypothesis that intensity, or rather, local intensity multipled by time of exposure, matters more. Suppose the UV light coming to your skin is x lux's in intensity and it lasts y seconds. The chance of you getting skin cancer on that spot is proportional to x*y. If this hypothesis is true, then we have a good strategy to achieve both goals at the same time, getting enough UV and avoiding skin cancer: alternate the part of your body exposed to the sun, and never let the sun light come to one small part of the skin for an extended period of time.

[Update]
Also see

Is there too much radiation from X-ray exams?

Western and Chinese medicine studying acupuncture: Difference

For a long time, I've noticed one big difference betweeen traditional Chinese medicine and western medical science in studying acupuncture: the latter almost always fails to specify the acupuncture points. People with basic knowledge of acupuncture, in fact, both acupuncture and moxibustion (AM), know that different acupuncture points serve different purposes, much like different drugs treat different diseases. Since western science publications list herb names when they're used in the research, and names of the AM points are already internationalized, I don't see why the names are not generally listed in equally scrutinized research papers.

Effect of Light at Sleep on Health

I'm interested in two issues related to light at sleep: lower limit in intensity of light not affecting child's growth, and effect on risk of cancer. I didn't find an article directly discussing the relationship of light to secretion of growth hormone (GH). But since GH and melatonin secretions are related ("Melatonin stimulates growth hormone secretion through pathways other than the growth hormone-releasing hormone"), and the effect of light intensity on melatonin is regularly studied, we can focus on the latter. This letter, by Steven Lockley, a Harvard Medical School doctor, shows the change of melatonin suppression in relation to light intensity (see Fig 1(B)). You can see when the light intensity reaches 50 lux, the level of melatonin quickly starts to be suppressed until about 200 lux.[note] In plain English, if you need a better night sleep, and growth for the child, the light should be kept below 50 lux. According to Wikipedia, 50 lux is about the light intensity you get at your "Family living room". So I believe unless there's direct light shining on your eyelids, as those from your night lights or street lights, you should have a piece of mind. If you must have some light, such as that on your digital clock, make sure it's red, which is at almost the exact opposite of blue in visible light spectrum. Again according to Wikipedia, the blue light has the most detrimental effect on melatonin secretion. Now you know why those clocks are red.

Light at sleep is also known to increase the risk of cancer, the most studied type of which may be breast cancer. See Dr. Weil's short note, and this 2005 article.
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[note] Other researchers did similar experiments, e.g., J.M. Zeitzer et al. in Am. J. Physiology in 2005. See its Fig 1(B). Their melatonin suppression onset started earlier at about 10 lux. But they had fewer data points.

Fat at buttock and thigh is good?

University of Oxford researcher's June 2010 article Gluteofemoral body fat as a determinant of metabolic health is generally cited by popular health science articles as saying it's a good thing to have gluteofemoral fat, or fat at buttocks and thighs. I wonder if it's a misreading. It seems to me the article is saying if you must have excessive fat, you would rather have it at gluteofemoral position, because it's a good place to store it. If we could find two identical people except for the fact that one is generally lean in the whole body and the other has a great amount of gluteofemoral fat, should we say the latter is more likely to be healthy?